Patent GB-1215740-A (GB)
Title: Pattern recognizing system
IPC: G06V10/44
Filed: 1968-07-25
Abstract: 1,215,740. Pattern recognition. FUJITSU Ltd. 25 July, 1968 [8 Aug., 1967], No. 35641/68. Heading G4R. In a pattern recognizing system, the pattern is scanned to give a plurality of horizontal scanning signals which are sequentially and repeatedly sampled to give vertical scanning signals, a rise or fall of the scanning signals being detected to give signals which are combined to give outputs representing lines, identified by their slopes, in the pattern, the vertical scanning signals being fed to means which detects an area within which the pattern exists, there being means for dividing the area into parts, relating the "outputs" above to the parts to determine whether particular lines exist in the parts, and classifying the pattern from the determination. In Fig. 5, signals from a horizontal scan across a character by a column of photo-cells 21 are binarized at 22 to feed units 23, 24. Unit 24 ORs together time-displaced samples from respective horizontal scan lines to simulate a series of almost vertical scans of the character. Unit 23 produces a pulse at each movement from background-to-character ("rising") and vice versa ("falling"), in each horizontal scan line. Units 26, 27 receive these "rising" and "falling" signals respectively, and act like unit 24, producing "horizontal rising" and "horizontal falling" signals. Units 25, 29, 30 are delays to give time for operation of units 28, 32 (see below). Unit 31 produces "vertical rising" and "vertical falling" signals from the delayed output of unit 24 in response to the background-tocharacter and character-to-background movements in it respectively. Unit 33 produces pulses for the upper and lower edges of positive slope oblique and negative slope oblique character line parts from logical combinations of the horizontal and vertical rising and falling signals, produces pulses for the upper and lower edges of horizontal line parts from the vertical rising and falling signals when not inhibited by concurrent presence of oblique signals applied via shift registers and produces pulses for the left and right edges of vertical line parts from combining the parallel outputs of shift registers fed with the horizontal rising and falling signals small gaps being eliminated (or the vertical line part pulses can be produced similarly to the horizontal line part pulses). Unit 28 constitutes a rectangle centred on the character by detecting character start, assuming character end is a predetermined delay after this, and detecting character top and bottom by using the character signals from unit 24 to gate ramps produced in synchronism with the simulated vertical scans of unit 24, to maximum and minimum capacitor stores. Unit 32 contains a counter used for specifying windows within the rectangle. Unit 34 integrates (counts) horizontal, vertical and oblique line part pulses from unit 33 in these windows, the integrators feeding threshold devices to identify horizontal, vertical, positive slope oblique and negative slope oblique character strokes at various positions which features are combined in unit 35 to identify the character.